powerpc/fsl_booke/32: introduce create_kaslr_tlb_entry() helper

Add a new helper create_kaslr_tlb_entry() to create a tlb entry by the
virtual and physical address. This is a preparation to support boot kernel
at a randomized address.
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Diana Craciun <diana.craciun@nxp.com>
Tested-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Scott Wood <oss@buserror.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/head_fsl_booke.S

@@ -1114,6 +1114,41 @@ __secondary_hold_acknowledge:
 	.long	-1
 #endif
 
+/*
+ * Create a 64M tlb by address and entry
+ * r3 - entry
+ * r4 - virtual address
+ * r5/r6 - physical address
+ */
+_GLOBAL(create_kaslr_tlb_entry)
+	lis     r7,0x1000               /* Set MAS0(TLBSEL) = 1 */
+	rlwimi  r7,r3,16,4,15           /* Setup MAS0 = TLBSEL | ESEL(r6) */
+	mtspr   SPRN_MAS0,r7            /* Write MAS0 */
+
+	lis     r3,(MAS1_VALID|MAS1_IPROT)@h
+	ori     r3,r3,(MAS1_TSIZE(BOOK3E_PAGESZ_64M))@l
+	mtspr   SPRN_MAS1,r3            /* Write MAS1 */
+
+	lis     r3,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@h
+	ori     r3,r3,MAS2_EPN_MASK(BOOK3E_PAGESZ_64M)@l
+	and     r3,r3,r4
+	ori	r3,r3,MAS2_M_IF_NEEDED@l
+	mtspr   SPRN_MAS2,r3            /* Write MAS2(EPN) */
+
+#ifdef CONFIG_PHYS_64BIT
+	ori     r8,r6,(MAS3_SW|MAS3_SR|MAS3_SX)
+	mtspr   SPRN_MAS3,r8            /* Write MAS3(RPN) */
+	mtspr	SPRN_MAS7,r5
+#else
+	ori     r8,r5,(MAS3_SW|MAS3_SR|MAS3_SX)
+	mtspr   SPRN_MAS3,r8            /* Write MAS3(RPN) */
+#endif
+
+	tlbwe                           /* Write TLB */
+	isync
+	sync
+	blr
+
 /*
  * Create a tlb entry with the same effective and physical address as
  * the tlb entry used by the current running code. But set the TS to 1.

arch/powerpc/mm/mmu_decl.h

@@ -139,6 +139,7 @@ extern unsigned long calc_cam_sz(unsigned long ram, unsigned long virt,
 extern void adjust_total_lowmem(void);
 extern int switch_to_as1(void);
 extern void restore_to_as0(int esel, int offset, void *dt_ptr, int bootcpu);
+void create_kaslr_tlb_entry(int entry, unsigned long virt, phys_addr_t phys);
 #endif
 extern void loadcam_entry(unsigned int index);
 extern void loadcam_multi(int first_idx, int num, int tmp_idx);